import uuid
import falcon
import mysql.connector
import simplejson as json
from core.useractivity import user_logger, admin_control, access_control, api_key_control
import config


class EnergyItemCollection:
    """
    Energy Item Collection Resource

    This class handles CRUD operations for energy item collection.
    It provides endpoints for listing all energy items and creating new items.
    Energy items represent specific energy types within energy categories.
    """
    def __init__(self):
        """Initialize EnergyItemCollection"""
        pass

    @staticmethod
    def on_options(req, resp):
        """Handle OPTIONS requests for CORS preflight"""
        _ = req
        resp.status = falcon.HTTP_200

    @staticmethod
    def on_get(req, resp):
        if 'API-KEY' not in req.headers or \
                not isinstance(req.headers['API-KEY'], str) or \
                len(str.strip(req.headers['API-KEY'])) == 0:
            access_control(req)
        else:
            api_key_control(req)
        cnx = mysql.connector.connect(**config.myems_system_db)
        cursor = cnx.cursor()

        query = (" SELECT id, name, uuid "
                 " FROM tbl_energy_categories ")
        cursor.execute(query)
        rows_energy_categories = cursor.fetchall()

        energy_category_dict = dict()
        if rows_energy_categories is not None and len(rows_energy_categories) > 0:
            for row in rows_energy_categories:
                energy_category_dict[row[0]] = {"id": row[0],
                                                "name": row[1],
                                                "uuid": row[2]}

        query = (" SELECT id, name, uuid, energy_category_id "
                 " FROM tbl_energy_items "
                 " ORDER BY id ")
        cursor.execute(query)
        rows = cursor.fetchall()
        cursor.close()
        cnx.close()

        result = list()
        if rows is not None and len(rows) > 0:
            for row in rows:
                meta_result = {"id": row[0],
                               "name": row[1],
                               "uuid": row[2],
                               "energy_category": energy_category_dict.get(row[3], None)}
                result.append(meta_result)

        resp.text = json.dumps(result)

    @staticmethod
    @user_logger
    def on_post(req, resp):
        """Handles POST requests"""
        admin_control(req)
        try:
            raw_json = req.stream.read().decode('utf-8')
        except Exception as ex:
            print(str(ex))
            raise falcon.HTTPError(status=falcon.HTTP_400,
                                   title='API.BAD_REQUEST',
                                   description='API.FAILED_TO_READ_REQUEST_STREAM')

        new_values = json.loads(raw_json)

        if 'name' not in new_values['data'].keys() or \
                not isinstance(new_values['data']['name'], str) or \
                len(str.strip(new_values['data']['name'])) == 0:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_ENERGY_ITEM_NAME')

        name = str.strip(new_values['data']['name'])

        if 'energy_category_id' not in new_values['data'].keys() or \
                new_values['data']['energy_category_id'] <= 0:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_ENERGY_CATEGORY_ID')
        energy_category_id = new_values['data']['energy_category_id']

        cnx = mysql.connector.connect(**config.myems_system_db)
        cursor = cnx.cursor()

        cursor.execute(" SELECT name "
                       " FROM tbl_energy_items "
                       " WHERE name = %s ", (name,))
        if cursor.fetchone() is not None:
            cursor.close()
            cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.ENERGY_ITEM_NAME_IS_ALREADY_IN_USE')

        cursor.execute(" SELECT name "
                       " FROM tbl_energy_categories "
                       " WHERE id = %s ",
                       (energy_category_id,))
        if cursor.fetchone() is None:
            cursor.close()
            cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_404, title='API.NOT_FOUND',
                                   description='API.ENERGY_CATEGORY_NOT_FOUND')

        add_value = (" INSERT INTO tbl_energy_items "
                     "    (name, uuid, energy_category_id) "
                     " VALUES (%s, %s, %s) ")
        cursor.execute(add_value, (name,
                                   str(uuid.uuid4()),
                                   energy_category_id))
        new_id = cursor.lastrowid
        cnx.commit()
        cursor.close()
        cnx.close()

        resp.status = falcon.HTTP_201
        resp.location = '/energyitems/' + str(new_id)


class EnergyItemItem:
    def __init__(self):
        pass

    @staticmethod
    def on_options(req, resp, id_):
        _ = req
        resp.status = falcon.HTTP_200
        _ = id_

    @staticmethod
    def on_get(req, resp, id_):
        if 'API-KEY' not in req.headers or \
                not isinstance(req.headers['API-KEY'], str) or \
                len(str.strip(req.headers['API-KEY'])) == 0:
            access_control(req)
        else:
            api_key_control(req)
        if not id_.isdigit() or int(id_) <= 0:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_ENERGY_ITEM_ID')

        cnx = mysql.connector.connect(**config.myems_system_db)
        cursor = cnx.cursor()

        query = (" SELECT id, name, uuid "
                 " FROM tbl_energy_categories ")
        cursor.execute(query)
        rows_energy_categories = cursor.fetchall()

        energy_category_dict = dict()
        if rows_energy_categories is not None and len(rows_energy_categories) > 0:
            for row in rows_energy_categories:
                energy_category_dict[row[0]] = {"id": row[0],
                                                "name": row[1],
                                                "uuid": row[2]}

        query = (" SELECT id, name, uuid, energy_category_id "
                 " FROM tbl_energy_items "
                 " WHERE id = %s ")
        cursor.execute(query, (id_,))
        row = cursor.fetchone()
        cursor.close()
        cnx.close()
        if row is None:
            raise falcon.HTTPError(status=falcon.HTTP_404, title='API.NOT_FOUND',
                                   description='API.ENERGY_ITEM_NOT_FOUND')
        result = {"id": row[0],
                  "name": row[1],
                  "uuid": row[2],
                  "energy_category": energy_category_dict.get(row[3], None)}
        resp.text = json.dumps(result)

    @staticmethod
    @user_logger
    def on_delete(req, resp, id_):
        admin_control(req)
        if not id_.isdigit() or int(id_) <= 0:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_ENERGY_ITEM_ID')

        cnx = mysql.connector.connect(**config.myems_system_db)
        cursor = cnx.cursor()

        cursor.execute(" SELECT name "
                       " FROM tbl_energy_items "
                       " WHERE id = %s ", (id_,))
        if cursor.fetchone() is None:
            cursor.close()
            cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_404, title='API.NOT_FOUND',
                                   description='API.ENERGY_ITEM_NOT_FOUND')

        cursor.execute(" SELECT id "
                       " FROM tbl_meters "
                       " WHERE energy_item_id = %s ", (id_,))
        rows_meters = cursor.fetchall()
        if rows_meters is not None and len(rows_meters) > 0:
            cursor.close()
            cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_400,
                                   title='API.BAD_REQUEST',
                                   description='API.ENERGY_ITEM_USED_IN_METER')

        cursor.execute(" SELECT id "
                       " FROM tbl_virtual_meters "
                       " WHERE energy_item_id = %s ", (id_,))
        rows_virtual_meters = cursor.fetchall()
        if rows_virtual_meters is not None and len(rows_virtual_meters) > 0:
            cursor.close()
            cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_400,
                                   title='API.BAD_REQUEST',
                                   description='API.ENERGY_ITEM_USED_IN_VIRTUAL_METER')

        cursor.execute(" SELECT id "
                       " FROM tbl_offline_meters "
                       " WHERE energy_item_id = %s ", (id_,))
        rows_offline_meters = cursor.fetchall()
        if rows_offline_meters is not None and len(rows_offline_meters) > 0:
            cursor.close()
            cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_400,
                                   title='API.BAD_REQUEST',
                                   description='API.ENERGY_ITEM_USED_IN_OFFLINE_METER')

        cursor.execute(" DELETE FROM tbl_energy_items WHERE id = %s ", (id_,))
        cnx.commit()

        cursor.close()
        cnx.close()
        resp.status = falcon.HTTP_204

    @staticmethod
    @user_logger
    def on_put(req, resp, id_):
        """Handles PUT requests"""
        admin_control(req)
        try:
            raw_json = req.stream.read().decode('utf-8')
        except Exception as ex:
            print(str(ex))
            raise falcon.HTTPError(status=falcon.HTTP_400,
                                   title='API.BAD_REQUEST',
                                   description='API.FAILED_TO_READ_REQUEST_STREAM')

        if not id_.isdigit() or int(id_) <= 0:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_ENERGY_ITEM_ID')

        new_values = json.loads(raw_json)
        if 'name' not in new_values['data'].keys() or \
                not isinstance(new_values['data']['name'], str) or \
                len(str.strip(new_values['data']['name'])) == 0:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_ENERGY_ITEM_NAME')

        name = str.strip(new_values['data']['name'])

        if 'energy_category_id' not in new_values['data'].keys() or new_values['data']['energy_category_id'] <= 0:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_ENERGY_CATEGORY_ID')
        energy_category_id = new_values['data']['energy_category_id']

        cnx = mysql.connector.connect(**config.myems_system_db)
        cursor = cnx.cursor()

        cursor.execute(" SELECT name "
                       " FROM tbl_energy_items "
                       " WHERE id = %s ", (id_,))
        if cursor.fetchone() is None:
            cursor.close()
            cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_404, title='API.NOT_FOUND',
                                   description='API.ENERGY_ITEM_NOT_FOUND')

        cursor.execute(" SELECT name "
                       " FROM tbl_energy_items "
                       " WHERE name = %s AND id != %s ", (name, id_))
        if cursor.fetchone() is not None:
            cursor.close()
            cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.ENERGY_ITEM_NAME_IS_ALREADY_IN_USE')

        cursor.execute(" SELECT name "
                       " FROM tbl_energy_categories "
                       " WHERE id = %s ",
                       (energy_category_id,))
        if cursor.fetchone() is None:
            cursor.close()
            cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_404, title='API.NOT_FOUND',
                                   description='API.ENERGY_CATEGORY_NOT_FOUND')

        update_row = (" UPDATE tbl_energy_items "
                      " SET name = %s, energy_category_id = %s "
                      " WHERE id = %s ")
        cursor.execute(update_row, (name,
                                    energy_category_id,
                                    id_,))
        cnx.commit()
        cursor.close()
        cnx.close()
        resp.status = falcon.HTTP_200

